The present invention relates to an apparatus which is available for cutting off a sheet like a textile fabric by applying an effectively connected pipe arrangement.
Normally, an automatically controlled sheet cutting apparatus is made available for cutting off a soft sheet like a textile fabric into a predetermined shape. Conventionally, a sheet feeding table, a cutting table, and a sheet take-out table, are sequentially disposed on the plane surface of any conventional sheet cutting apparatus. Typically, such a conventional sheet cutting apparatus incorporates an air absorber and a filtering unit, which are respectively connected to the sheet feeding table, the sheet cutting table, and the sheet take-out table via a number of pipes. Normally, any conventional sheet cutting apparatus is furnished with an endless conveyer unit and an air-absorbing cleaner so that the conveyer unit can be prevented from being clogged with dust.
In order to convey a fabric forward in slightly afloat condition, those conventional feeding tables and take-out tables externally blow air via a number of through holes provided on the surface of these tables. Furthermore, in order to secure the fabric, the fabric is absorbed against the surfaces of these tables provided for the cutting apparatus. The air-absorbing cleaner removes fibrous dust from the endless conveyer by means of absorption.
An air compressing source is provided for the sheet feeding table and also for the sheet take-out table. On the other hand, the cutter unit and the cleaner are respectively provided with an air absorber and a filter.
To solve those technical problems cited above, typically, there is such a proposal to commonly make use of part of air-absorbing units and filtering units to save provision of the air-absorbing unit and the filtering unit for each cleaner so that spacewise and costwise problems can be eliminated.
For example, the Japanese Patent Publication No. 62-50280 of 1987 discloses such a structure in which an air-absorbing unit provided for a cutting unit is concurrently made available for a cleaner unit except for a pneumatic source which is discretely provided for a feeding table. Nevertheless, this prior art does not disclose such a specific technical thought for concurrently availing of the air-absorbing unit as the pneumatic source.
Since any of those conventional sheet cutting apparatuses including the one proposed by the above-cited Japanese Patent Publication No. 62-50280 of 1987 cannot concurrently make use of components in common with each other beyond the proposed scope, spacewise and costwise problems adversely affect operating efficiency of these conventional apparatuses.
In order to improve operating efficiency, if there were such a trial to concurrently use the air-absorbing unit as the pneumatic source, it will not only result in the need to invert the flow of air, but it will also generate an excessive flow rate when the flow rate of absorbed air applicable to the cutting unit is introduced to the pneumatic source available for the feeding table.
On the other hand, if each blower were provided with a constant capacity, absorptive force may excessively be intensified according to the condition to execute the cutting process. In order to adjust pressure, typically, the Japanese Laid-Open Patent Publication No. 60-52299 of 1985 discloses provision of valves. Nevertheless, this art cannot properly maintain energetic efficiency.
Therefore, in order to reasonably solve those technical problems inherent in conventional cutting apparatuses, the invention hereby provides a novel sheet cutting apparatus which concurrently makes use of an air-absorbing unit for the cutting unit by way of sharing it with the cleaning unit, and yet, the invention also makes use of this air-absorbing unit as the pneumatic source of the sheet feeding table. To securely materialize this, the invention provides a special pipe arrangement and a control system.